1. Field of the Invention
The present invention relates to an optical device and a mobile apparatus mounted with the optical device.
2. Description of the Related Art
An optical device has been proposed which measures a distance to an object based on a phase difference between the light projected onto the object and the light reflected from the object (see, for example, Japanese Patent Laid-Open No. 2004-257935). Conventionally, in order to detect an object or measure a distance thereto over a wide range, a cylindrical lens is arranged in front of a projector, and the curvature of the lens is increased to achieve light projection over the wide range. As the light source, a laser light source such as a laser diode is used for measurement of distance with high accuracy. Further, a screen has been proposed which can provide a viewer with wider and brighter video images by making the images pass through a lenticular lens.
The increase in curvature of the cylindrical lens, however, would lead to an increase in thickness of the lens, which hinders reduction in size of the optical device.